Method for attaching sliced aligned filaments to a backing



June 25, 1968 D. R. HULL 3,390,034

METHOD FOR ATTACHING SLICED ALIGNED FILAMENTS TO A BACKING Filed April30, 1965 /BACKING FABRIC vfiwmmvmflmmmmw iazmz ./-CARD CLOTHING. BACKINGW www rw; 11'111'. mocwmmcygzm m 6; o

L Mi -M 1' v; comomnnuusnrs w conmusaswssnowm i} Q mmmnusssuw W A 1 Snmsmmr ASSEMBLY ,-cARo CLOTHING mas -conrom5o mums ADHESIVE LAYER aouomsA FIBER ENDS T0 mums \BAOKING FABRIC i I CONTQRTED FILE FILAHENTS 4"'4'4'w4'42 -1Lza4w-ADHESIVE LAYER BACKING FABRIC INVENTOR DONALD R.HULL BY W g/4% ATTORNEY United States Patent 3 390,034 METHOD FORA'ITACHING SLICED ALIGNED FILAMENTS T0 A BACKING Donald Robert Hull,Wilmington, DeL, assignor to E. I. du Pont de Nemours and Company,Wilmington, Del., a corporation of Delaware Continuation-iu-part ofabandoned application Ser. No. 239,675, Nov. 23, 1962. This applicationApr. 30, 1965, Ser. No. 453,564

5 Claims. (Cl. 156-72) This application is a continuation-in-part ofcopending application Ser. No. 239,675 filed Nov. 23, 1962 nowabandoned.

This invention relates to an improved means for attaching the ends offilaments to a backing and, more particularly, to an improved processfor holding a plurality of aligned filaments in fixed relationship whilethe ends of the filaments are attached to a backing.

Heretofore various techniques have been proposedfor holding alignedfilaments in fixed relationship in order that they could be more readilytransported and processed, e.g. attached to a backing. The majority ofthese techniques have involved complex systems using mechanical bridges,holding blades and the like to attach neighboring filaments together.Although often suitable for certain purposes, each of these methods hasnevertheless been attended by certain economic or quality disadvantagesas to make their use unsatisfactory, sometimes impractical, forcommercial purposes.

It is an object of this invention to provide a novel technique forkeeping aligned filaments in fixed relationship to permit adequateattachment of the filament ends to a backing. Another object is toprovide an improved process for attaching aligned filaments to abacking. A further object is to provide a novel process for controllingthe uniformity of distribution of filaments when the ends of thesefilaments are attached to a backing to provide backed textile articles.Other objects will appear from the remainder of the specification andclaims.

The above objects are accomplished by a process for making textilearticles wherein first there is provided a body having a plurality offilaments aligned in generally the same direction within the body andhaving at least one substantially planar surface defined by filamentends. Thereafter a supported medium, such as an assembly of parallelwires embedded in a backing, is positioned within the body adjacent theplanar surface so as to extend throughout a predetermined depth inperpendicular relationship to the planar surface. Since the medium, i.e.wires, extend in the same general direction as the filaments they thusserve to reinforce, support, and rigidify the filament alignment withinthe body of filaments. Subsequently the filamentary body is slicedtransversely to the direction of the filaments in a plane parallel tothe mentioned planar surface and just beyond the extremity of themedium, i.e. the ends of wires, to obtain an assembly of aligned shortfilaments embedded in the supported medium. Finally the free cut ends ofthe filaments are adhered to a backing and the supported medium isremoved from the backed filaments.

The accompanying drawings schematically illustrate an embodiment of theprocess of the invention. FIGURE 1 is a representation of a side View ofthe supported reinforcing wires embedded in one end of the filamentarybody and extending to a predetermined depth D. FIGURE 2 depicts a sideview of the cut section of the filamentary assembly containing theembedded wires after the assembly in FIGURE 1 is sliced along the planeA-A'. Such slice is effected beyond the depth of penetration of theWires and, in a preferred embodiment, is so directed as to provide areinforced filamentary sheet having a 3,390,034 Patented June 25, 1968thickness no greater than twice that of D. FIGURE 3 represents the sideview of the cut section illustrated in FIGURE 2 after a backing has beenattached to the free cut ends of the filaments. In addition toreinforcing the alignment of fibers during the slicing step, thesupported wires also facilitate the application of pressure, with onlyminimum distortion of fiber alignment, necessary to adhere the structureto a backing. FIGURE 4 represents a side view of the textile articleresulting from removal of the supported wires from the assembly shown inFIGURE 3.

A suitable method for practicing the present invention will now bedescribed in greater detail. A tow consisting of a number of highlycrimped continuous filaments is assembled in an open-ended mold suchthat the ends of each filament are aligned in the same direction towardthe Open faces of the mold. The filamentary assembly is sliced with aknife in a plane parallel with one open face of the mold andtransversely to the direction of the filaments protruding from one endof the mold to provide a smooth face of filament ends. Thereafter asheet of card wire clothing attached to a flat backing is inserted intothe cut face of filament ends so that the ends of the filaments areembedded inside the wire clothing to the depth of the backing holdingthe wires. The filamentary assembly is then pushed or extruded from themold a short distance corresponding to approximately the desired pileheight of the textile product. The filamentary assembly embedded in thewire clothing is then sliced with a knife transversely to the directionof the filaments at a distance just beyond the ends of the wires,leaving an assembly of cut aligned filaments held together by embedmentin the wire clothing such that the most recently cut ends of thefilaments protrude slightly beyond the ends of the embedding wires. Thefreshly cut face or planar surface consisting of filament ends isapplied to a suitable backing containing a layer of an adhesivecomposition by pressing the assembly of filaments and wires firmlyagainst the coated backing so as to embed the filament ends into theadhesive layer. After drying or curing of the adhesive to firmly attachthe ends of the filaments to the backing material, the sheet of cardwire clothing is removed, leaving a hacked article containing a numberof filaments aligned in the same direction protruding as a pile layerfrom the backing to which they are firmly attached.

The invention is broadly applicable to filamentary materials in variousforms; for example, carded webs of substantially aligned staple fibersor bodies of substantially aligned filamentary structures prepared froma warp of sliver, top, roping, roving, tow, stutter box crimped tow,steam bulked tow, steam crimped continuous filament yarn, gear crimpedcontinuous filament yarn, twist set-back twisted continuous filamentyarn, knife edge crimped continuous filament yarn, two-component bulkycontinuous filament yarn, spun yarns, and many others. Similarly theinvention is broadly applicable to filaments of widely varyingcomposition, both synthetic and naturally occurring.

Typical of the fibers and filaments which may be employed are those madeof polyamides, such as poly(hexamethylene adipamide),poly(meta-phenylene isophthalamide), poly(hexamethylene sebacamide),polycaproamide, copolyamides and irradiation grated polyamides,polyesters and copolyesters such as condensation products of ethyleneglycol with terephthalic acid, ethylene glycol with a /10 mixture ofterephthalic/isophthalic acids, ethylene glycol with a 98/2 mixture ofterephthalic/5- (sodium sulfo)-isophthalic acids, andtrans-p-hexahydroxylylene glycol with terephthalic acid, self-elongatingethyleneterephthalate polymers, polyacrylonitrile, co-polymers ofacrylonitrile with other monomers such as vinyl acetate, vinyl chloride,methyl acrylate, vinyl pyridine, sodium styrene sulfonate, terpolymersof acrylonitrile/ methylacrylate/ sodium styrene sulfonate made inaccordance with US. Patent 2,837,501, vinyl and vinylidene poly mers andco-polymers, polycarbonates, polyacetals, polyethers, polyurethanes suchas segmented polymers described in U.S. Patents 2,957,852 and 2,929,804,polyesteramides, polysulfonamides, polyethylenes, polypropylenes,fluorinated and/or chlorinated ethylene polymers and copolymers, (e.g.,polytetrafiuoroethylene, polytrifluorochloroethylenes) cellulosederivatives, such as cellulose acetate, cellulose triacetate, compositefilaments such as, for example, a sheath of polyarnide around a core ofpolyester as described in US. Patent 3,038,236, and self-crimpedcomposite filaments, such as two acrylonitrile polymers differing inionizable group content cospun side by side as described in US. Patent3,038,237, regenerated cellulose, cotton, wool, glass, metal, ceramicand the like. Blends of two or more synthetic or natural fibers may beused, as well as blends of synthetic and natural. Other fibers such assilk, animal fibers such as mohair, angora, vicuna are also suitable.

The initial body composed of a plurality of filaments aligned ingenerally the same direction may be prepared from a wide variety offorms of fibers and filaments, having any of the above-mentionedcompositions, such as, for example, continuous monofilaments, continuousmultifilaments, carded webs, warp, sliver, top, roping, roving, tow,bulked tow, bulked continuous filament yarn, spun yarn, batts, felts,papers and other non-woven Webs, and the like. The fibers and filamentsused as raw material may be either crimped or uncrimped, bulked orunbulked, drawn or undrawn or twisted or untwisted. The denier of thefilaments is not critical and may vary from about 0.5 to about 50 denieror even higher.

In a preferred embodiment of the invention the filaments are contorted(e.g. crimped) as described in C. R. Koller US. Patent 3,085,922 suchthat the body employed is a porous material having a plurality ofcontorted filamentary structures which overlap, are aligned generally inthe same direction, are interconnected throughout the three dimensionsof the material and the material has a fiber density below 25 lbs./ft.Although a description of these materials including definitions of theterms used in connection therewith is fully set forth in the aboveKoller patent, the disclosure of which is specifically incorporatedherein by reference, they will be briefly mentioned herein. By contortedit is meant that the profile (i.e. side elevation) of an individualfilament is irregular (i.e. not straight) when the filament is viewedfrom at least one side. In addition to being contorted, it is necessarythat such filamentary structures overlap adjacent structures throughoutthe three dimensions of the article. By the term overlap is meant thatin at least one view, a filamentary structure crosses over, with orwithout touching or attachments, an adjacent filamentary structure.Furthermore it is critical to such structures that the contortion andoverlapping of the filamentary structures do coact or are allowed tocoact with one another. By coact" is meant that the contortion andrelative placement of the filamentary structures are such that theyassist one another in producing and maintaining the claimed structuresboth with respect to the general alignment of the filamentary structuresand their spacing with respect to each other to achieve the desirabledensities contemplated.

The adhesives which may be used when applying the backing are varied. Byadhesive or glue is meant the material used to cause the filamentarystructures and sheet materials to adhere to the backing or is meant thematerial used to constitute the backing Illustrative adhesives are:chloroprene rubber, elastomeric foams and sponges, butadiene-styrenerubber, polyvinyl chloride resin (e.g. those in combination with eithera polymeric plasticizer or a monomeric plasticizer curable afterapplication of the adhesive), polyurethane resins, polyamide copolymerof hexamethylene diamine and adipic and sebacic acids, casein resin, andepoxy resins such as the diepoxide of 2,2-bis(parahydroxyphenyl)propane. Illustrative backings are: woven fabricssuch as burlap, canvas, and nylon scrim fabrics, knit fabrics such asnylon tricot, nonwoven fabrics such as polyethylene or polypropylenefiber webs, resin bonded polyethylene terephthalate fiber webs, papersof cellulosic and/or synthetic fibers, paper felts such as asphaltimpregnated cellulose, elastomeric foams and sponges, plastic films suchas from polyethylene terephthalate, polypropylene and polyvinyl chloridepolymers, metal foils and rigid sheets such as fiber glass reinforcedpolyester resins, metals, ceramics and wood, elastic, stretchable orshrinkable fabrics and films, and the like.

For practicing this invention wire holding means may be employed whichwill provide a network of supported, elongated, spaced apart, wire-likeprotrusions aligned in the same genera-l direction such that thewire-like protrusions can be inserted between the ends of the filamentsconstituting one face of the aligned filamentary assembly. In the casewhere the filaments are contorted, as is preferred, the wires may simplybe straight. With straight filaments (e.g., uncrimped) it is desirableto employ in connection there-with card clothing composed of bent wires.Whether they are bent or straight, all of the wires will normally besupported in a continuous backing which has suificient rigidity to beable to apply a pressure to the supported assembly of wires in order toattach the free ends of the filaments to a backing. The wires may bemade of metal, synthetic plastic compositions, ceramic, or any otherrelatively rigid material.

If desired, a small amount of a binder composition may be employed inthe practice of this invention in addition to the wire clothing in orderto provide a greater degree of stifiness. The hinder or stifi'eningagent when employed can be applied to the assembly of aligned filamentsin the mold prior to engagement of the wire clothing with the assembledfilaments. In this instance, the material can be applied uniformlythroughout the length of the assembly of filaments so as to provide acoating on the filaments to stiffen them and/ or to bond some of theadjacent filaments together at a number of crossing points of thefilaments. Alternatively, the material can be applied to the free cutends of the filaments opposite the engaged ends after the wire-engagedfilamentary assembly is sliced off, in order to stiffen and/or bondtogether the filaments for a short distance along their lengths near thefree-cut ends.

The binders which can optionally be used in accordance with theinvention may be either soluble or insoluble, and may be eitherthermoplastic in nature or may be thermosetting which may then bereacted with a curing agent to form a cured polymer depending upon theuse desired. If it is desired to remove the binder a soluble binder willbe employed which may be either organic-soluble or watersoluble.Suitable organic-soluble binders include natural rubber or syntheticelastomers (e.g., chloroprene, butadienestyrene copolymers,butadiene-acrylonitrile copolymers), which may be used in the form of alatex dispersion or emulsion or in the form of a solution, vinyl acetatepolymers and copolymers, acrylic polymers and copolymers such as ethylacrylate, methyl acrylate, butyl acrylate, methyl methacrylate, acrylicacid/ acrylic and methacrylic ester copolymers, cellulose nitrate,cellulose acetate, cellulose triacetate, polyester resins such asethylene terephthalate/ethylene isophthalate copolymers, polyurethanessuch as the polymer from piperazine and ethylene bis-chloroformate,polyamide polymers, and copolymers, methoxymethyl polyamides, vinylchloride polymers and copolymers such as vinyl chloride/vinylidenechloride copolymer latices. Alcohol soluble polyamide resins are alsosuitable organic-soluble binders. Suitable water-soluble binders includematerials such as polyvinyl alcohol, sodium alginate, acrylic acidpolymers and copolymers such as polyacrylic acid, carboxymethylcellulose, hydroxyethyl cellulose, dextrins, animal glue, soybean glueand sodium silicate. Suitable binders which are insoluble in organicsolvents include polytetrafiuoroethylene and ureaformaldehyde resinlatices.

Additional suitable binder compositions include chlorosulfonatedpolyethylene; butyl rubbers, such as isobutylene/isoprene copolymers;polyhydrocarbons, such as polyethylene, polypropylene and the like andcopolymers thereof; high molecular weight polyethylene glycols soldunder the trade name of Polyox; epoxide resins, such as the diepoxide ofbisphenols and glycols; polystyrene; alkyd resins, such as polyesters ofglycerol with phthalic or maleic acid; polyester resins such as frompropylene glycolmaleic anhydride-styrene; phenol-formaldehyde resins;resorcinol-formaldehyde resins; polyvinyl acetals, such as polyvinylbutyral and polyvinyl formal; polyvinyl others, such as polyvinylisobutyl ether; starch, zein, casein, gelatine, methyl cellulose, ethylcellulose, polyvinyl fluoride, natural gums, polyisobutylene, shellac,terpene resins and rosin soaps. Segmented polymers, such as spandexpolymers, polyether amides, polyether urethanes (eg. those in US.2,929,800) and polyester/urethanes are also suitable.

When inserting the wire clothing into one end of the filamentaryassembly, the Wires should protrude a distance just short of the finalpile thickness desired in the final textile article, so that only a veryshort length of each filament protrudes beyond the free ends of thewires at the time the transverse cut is made through the assembly offilaments. However, the amount of protrusion of the free ends of thefilaments beyond the inserted wires may be varied somewhat dependingupon whether or not a stiifening agent or binder is employed in additionto the wire clothing to provide added strength and adherence to permitboth cutting of the transverse slice as well as attaching of the slicedassembly of filaments and wires to a backing.

The present invention provides a method for attaching an assembly ofaligned filaments to a backing without the need for any stiffening agentor binder composition for holding the aligned filaments together duringcutting and during attachment of the filaments to the backing. Anotheradvantage of the present invention is that less pressure is required inattaching the wire-held filaments to a backing than that required inpressing an assembly of filaments held together with binder compositionin the absence of any wire-holding means. The present invention is ofparticular advantage in the preparation of backed textile articles orpile fabrics having a medium to high fiber density in the pile layer;that is, such fabrics having a fiber density in the pile of at least onepound per cubic foot. Also, the invention is most useful when preparingpile fabrics having a pile thickness of at least inch.

The present invention invention may be used for preparing a wide varietyof backed textile articles or pile fabrics such as floor coverings,carpets, tiles, upholstery fabrics, furs and fleeces, single and doublefaced blankets, suedes, and the like.

The following example illustrates a specific embodiment for practicingthe present invention, but is not intended to be limiting in anyrespect.

Example The fiber used is a tow of 120 ends of continuous filament nylonyarns (102.0 denier, 68 filaments, /2 Z twist, trilobal cross section).This tow is bulked with steam under the conditions disclosed in Example2 in Table III of Belgian Patent 573,230 and thereafter cut transverselyto the yarns into 18" long sections. A number of these sections areassembled side-by-side in a metal mold 30" x 30" x 12" such that theyarns are all aligned in the same direction with their ends directedtowards opposite open faces of the mold (30" x 30" faces). The yarns arecompressed laterally to compact them to a density of 2.95 lbs./ cu. ft.Excess fiber protruding from the open top and bottom faces of the moldis trimmed off to provide a uniform surface of cut fiber ends. Onto thetop surface of the cut fiber ends of this assembly of fibers is pressed2. flexible sheet (29% x 29 /2") covered with card clothing such thatthe wires of the card clothing penetrate almost completely into thefiber assembly. This flexible card clothing sheet is made by abuttingtogether strips of 1 /2 wide card clothing and cementing the backs ofthese strips to one face of a burlap fabric. The card clothing consistedof No. 26 HX wires projecting perpendicularly from a four-ply rubberizedfabric with the wires projecting and spaced 4 rows, 3 twill, 8 noggs soas to give 128 points per square inch.

The fiber assembly is then pushed out of the top of the mold a distanceof about /2" by applying a force on a plate against the bottom face ofthe fiber assembly. The fiber assembly is then sliced transversely tothe fibers in a plane parallel with the card clothing sheet and -at adistance of about Ms beyond the ends of the card clothing wires. Thus,the flexible sheet of card clothing with a layer of approximately /2long fibers intermingled with the card clothing wires is removed fromthe fiber assembly. The layer of fibers is aligned generallyperpendicular to the backing of the card clothing and held in thisposition by the card clothing wires. This assembly is readily handledand moved without loss of fibers.

The sheet of card clothing with the cut layer of fibers is pressed ontoa layer of rubber adhesive coated onto one side of burlap fabric so thatthe cut ends of the fibers protruding from the card clothing areembedded in the adhesive. The assembly is held together under lightpressure until the adhesive layer sets by evaporation of the adhesivesolvent. The ends of the fiber are well bonded to the burlap backing.The card clothing is removed from the pile fiber. There is obtained asoft pile fabric suitable for use as a carpet.

Although the invention has been described as particularly applicable tothe lamination of porous filamentary bodies to a backing, it is to beunderstood that the utilization of card clothing in the manner describedto enable uniform and effective slicing of the fibrous bodies is also anovel and highly useful feature of the invention. Thus this techniquefor slicing the fibrous body may be practiced as an intermediateprocessing step for obtaining the pile layer per se, e.g. withoutimmediately laminating such to a backing. If desired, an adhesivecomposition may be applied to a face of the sliced, fibrous body portionprior to removal of the card wire clothing therefrom.

What is claimed is:

1. Method for slicing a filamentary body comprising the steps of:

(a) providing a filamentary body in the form of a porous material havinga plurality of contorted synthetic organic polymeric filamentarystructures, said structures overlapping and being aligned generally inthe same direction, said filamentary structures being interconnected bya small amount of an organic binder composition at a plurality ofcontact points uniformly throughout the three dimensions of saidmaterial and said material having a fiber density up to about 2.95lbs./ft. said body having at least one substantially planar surfacedefined by filament ends,

(b) placing card wire clothing in contact with said planar surface ofsaid body and causing penetration of the card wires throughout apredetermined depth in said body in generally parallel relationship withsaid filaments to reinforce the alignment of said fi1aments,

(0) slicing said body in a plane substantially parallel to said planarsurface and beyond said predetermined depth, and

(d) removing said card wire clothing therefrom.

2. Method of claim 1 wherein an adhesive composition is applied to thefree cut ends of the severed reinforced portion of said body prior toremoval of said card wire clothing therefrom.

7 8 3. Method for attaching aligned filaments to a backing (d) adheringthe free cut ends of the severed, reincomprising the steps of: forcedportion of said body to a backing and remov- (a) providing a filamentarybody in the form of a ing said card wire clothing therefrom.

porous material having a plurality of contorted syn- 4. Method of claim3 wherein the slicing of said body thetic organic polymeric filamentarystructures, said 5 is effected to yield a severed, reinforced portionhaving structures overlapping and being aligned generally a thickness ofone to two times said predetermined disin the same direction, saidfilamentary structures betance. ing interconnected by a small amount ofan organic 5. Method of claim 3 wherein an adhesive composition bindercomposition at a plurality of contact points is applied to the free cutends of the severed reinforced uniformly throughout the three dimensionsof said 10 portion of said body prior to adhering said portion to amaterial and said material having a fiber density up backing. to about2.95 lbs./ft. said body having at least one References Citedsubstantially planar surface defined by filament ends, (b) placing cardwire clothing in contact with said UNITED STTES PATENTS planar surfaceof said body and causing penetration 15 $136,005 6/1964 Reltel'er 19-414of the card wires throughout a predetermined depth 3,271,216 9/1966Keller 156-454 X in said body in generally parallel relationship with3,287,196 11/1956 Koller 156254 said filaments to reinforce thealignment of Said 3,290,729 12/1966 Maynard 19*114 fil t 3,334,0068/1967 Koller 161-170 X (c) slicing said body in a plane substantiallyparallel 20 to said planar surface and beyond said predeter- EARLBERGERT P Examine"- mined depth, and HAROLD ANSHER, Assistant Examiner.

3. METHOD FOR ATTACHING ALIGNED FILAMENTS TO A BACKING COMPRISING THESTEPS OF: (A) PROVIDING A FILAMENTARY BODY IN THE FORM OF A POROUSMATERIAL HAVING A PLURALITY OF CONTORTED SYNTHETIC ORGANIC POLYMERICFILAMENTARY STRUCTURES, SAID STRUCTURES OVERLAPPING AND BEING ALIGNEDGENERALLY IN THE SAME DIRECTION, SAID FILAMENTARY STRUCTURE BEINGINTERCONNECTED BY A SMALL AMOUNT OF AN ORGANIC BINDER COMPOSITION AT APLURALITY OF CONTACT POINTS UNIFORMLY THROUGHOUT THE THREE DIMENSIONS OFSAID MATERIAL AND SAID MATERIAL HAVING A FIBER DENSITY UP TO ABOUT 2.95LBS./FT3, SAID BODY HAVING AT LEAST ONE SUBSTANTIALLY PLANAR SURFACEDEFINED BY FILAMENT ENDS, (B) PLACING CARD WIRE CLOTHING IN CONTACT WITHSAID PLANAR SURFACE OF SAID BODY AND CAUSING PENETRATION OF THE CARDWIRES THROUGHOUT A PREDETERMINED DEPTH IN SAID BODY IN GENERALLYPARALLEL RELATIONSHIP WITH SAID FILAMENTS TO REINFORCE THE ALIGNMENT OFSAID FILAMENTS, (C) SLICING SAID BODY IN A PLANE SUBSTANTIALLY PARALLELTO SAID PLANAR SURFACE AND BEYOND SAID PREDETERMINED DEPTH, AND (D)ADHERING THE FREE CUT ENDS OF THE SEVERED, REINFORCED PORTION OF SAIDBODY TO A BACKING AND REMOVING SAID CARD WIRE CLOTHING THEREFROM.